(a) Technical Field
Embodiments of the present invention generally relate to a liquid crystal display.
(b) Description of the Related Art
Liquid crystal displays are now widely used as one type of flat panel display. A liquid crystal display has two display panels on which field generating electrodes such as pixel electrodes and a common electrode are formed, and a liquid crystal layer that is interposed between the panels. Voltages are applied to the field generating electrodes so as to generate an electric field over the liquid crystal layer, and the alignment of liquid crystal molecules of the liquid crystal layer is determined by the electric field. Accordingly, the polarization of incident light is controlled, thereby performing image display.
The liquid crystal display further has thin film transistors connected to pixel electrodes, respectively, and a plurality of signal lines such as gate lines and data lines for controlling them.
Among the LCDs, a vertical alignment (VA) mode LCD, which aligns LC molecules such that their long axes are perpendicular to the panels in the absence of an electric field, is spotlighted because of its high contrast ratio and wide reference viewing angle. Here, the reference viewing angle implies a viewing angle that is 1:10 in contrast ratio, or a critical angle of gray-to-gray luminance reversion.
In order to approximate side visibility to front visibility in the vertical alignment mode LCD, a method of causing a difference in transmittance by dividing one pixel into two sub-pixels and applying different voltages to the two sub-pixels has been suggested.
An example of the method includes applying the same voltage to two sub-pixels and dropping the voltage of one sub-pixel by using a separate switching element. However, when employing this method, since the LCD should be provided with a plurality of signal lines and a plurality of contact holes, the aperture ratio is low.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.